Abstract
As a method of processing cemented carbide, wire electrical discharge machining (WEDM) is generally used. However, typical surface defects, such as microcraters, cracks and recast layer, cause a substantial deterioration in surface integrity. Therefore, it is necessary to eliminate these defects by some methods. An on-the-machine surface modification technology has been proposed in recent years. The surface defects are completely eliminated by introducing surface integrity cut (SI-cut) after applying a large number of WEDM finishing cuts. In this study, the surface integrity after SI-cut (SI-cut surface) is examined using bending test and evaluating transverse rupture strength (TRS). The results showed that TRS after SI-cut is lower than that as received. This is caused by the lack of cobalt which is the bonding material in cemented carbide near the surface during SI-cut process. This cobalt-poor layer is so hard and brittle, and leads to the decrease in TRS. The TRS after SI-cut becomes larger by increasing wire feed rate, that is, reducing the cobalt-poor layer in SI-cut process.
